How would sub-Saharan Africa north of the Limpopo have developed if the Europeans hadn't colonized it and had left their coastal forts in West Africa around 1850 after the end of the Transatlantic slavetrade.Disregard the small Portugese coastal settlements as they are of limited consequence.

Moslem slave hunters are still a problem in this scenario.11 million African slaves went east (mainly to Arabia but a few of them to India and beyond), 12 million across the Atlantic.

What happens to:

- Statebuilding/adequate defence- Economic development and modernization- Healthcare and education

(Please don't use this thread to discuss whether such as scenario was likely or not. I am aware that it would have been highly unlikely for a number of reasons)